Methine and Azo dye-containing dye mixtures

ABSTRACT

Dye mixtures include one or more pyridone dyes of the formula ##STR1## where M is a pyridone or triazolopyridone radical which is linked to the thiazole ring via nitrogen or CH and the rest of the radicals are each as defined in the description, 
     and one or more azo dyes of the formula 
     
         D--N=N--K, 
    
     where D is the radical of a diazo component of the pyrrole, thiophene, pyrazole, thiazole, isothiazole, triazole, thiadiazole, benzothiophene, benzothiazole, benzisothiazole, pyridothiophene, pyrimidothiophene, thienothiophene or aniline series, and 
     K is the radical of a coupling component of the aminothiazole, aniline or tetrahydroquinoline series, and are useful for thermal transfer.

The present invention relates to novel dye mixtures including one or more pyridone dyes of the formula I ##STR2## where R¹ and R² are independently of each other C₁ -C₁₀ -alkyl with or without substitution by C₁ -C₄ -alkoxycarbonyl, C₁ -C₄ -alkoxycarbonyloxy, whose alkyl chain may in each case be interrupted by an oxygen atom in ether function, or phenyl and with or without interruption by from 1 to 4 oxygen atoms in ether function, C₅ -C₇ -cycloalkyl, C₃ -C₄ -alkenyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, or R¹ and R² are together with the nitrogen atom joining them together a 5- or 6-membered saturated heterocyclic radical with or without further hetero atoms,

R³ is C₃ -C₁₀ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl or thienyl, C₅ -C₇ -cycloalkyl, and

M is a radical of the formula ##STR3## where X is nitrogen or CH,

R⁴ is hydrogen, C₁ -C₆ -alkyl or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl,

R⁵ is cyano, carbamoyl, mono- or di(C₁ -C₈ -alkyl)carbamoyl, carboxyl, C₁ -C₈ -alkoxycarbonyl or benzimidazolyl,

R⁶ is hydrogen, C₁ -C₁₀ -alkyl with or without substitution by phenyl, phenoxy, cyclohexyloxy or pyrazolyl and with or without interruption by from 1 to 4 oxygen atoms in ether function, C₅ -C₇ -cycloalkyl or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, or a radical of the formula NB¹ B² where B¹ and B² are independently of each other hydrogen, C₁ -C₁₀ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, C₁ -C₉ -alkanoyl, C₁ -C₈ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl, pyridylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted benzoyl, pyridylcarbonyl or thienylcarbonyl, and

one of the two radicals A and E is nitrogen and the other is a radical of the formula C--R⁷, where R⁷ has the meaning of C₁₀ -alkyl, with or without phenyl, phenoxy, cyclohexyloxy or pyrazolyl substitution and with or without interruption by from 1 to 4 oxygen atoms in ether function, of C₅ -C₇ -cycloalkyl or of unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl,

and one or more azo dyes of the formula II

    D--N=N--K                                                  (II),

where

D is a radical of the formula ##STR4## where L¹ is nitro, cyano, C₁ -C₆ -alkanoyl, benzoyl, C₁ -C₈ -alkoxycarbonyl, C₁ -C₈ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl or a radical of the formula --CH═T, where T is hydroxyimino, C₁ -C₄ -alkoxyimino or a radical of an acidic-CH compound H₂ T,

L² is hydrogen, C₁ -C₆ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, halogen, hydroxyl, mercapto, unsubstituted or phenyl- or C₁ -C₄ -alkoxy-substituted C₁ -C₆ -alkoxy, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenoxy, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylthio, C₁ -C₈ -alkylsulfonyl or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl,

L³ is cyano, C₁ -C₈ -alkoxycarbonyl or nitro,

L⁴ is hydrogen, C₁ -C₆ -alkyl, phenyl or tolyl,

L⁵ is C₁ -C₆ -alkyl, phenyl or tolyl,

L⁶ is hydrogen, cyano, C₁ -C₈ -alkoxycarbonyl, C₁ -C₆ -alkanoyl, thiocyanato, halogen or nitro,

L⁷ is nitro, cyano, C₁ -C₆ -alkanoyl, benzoyl, C₁ -C₈ -alkoxycarbonyl, C₁ -C₈ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl or a radical of the formula --CH═T, where T is as defined above,

L⁸ is hydrogen, C₁ -C₆ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, cyano, halogen, unsubstituted or phenyl- or C₁ -C₄ -alkoxy-substituted C₁ -C₆ -alkoxy, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylthio, C₁ -C₈ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl or C₁ -C₈ -alkoxycarbonyl,

L⁹ is cyano, unsubstituted or phenyl-substituted C₁ -C₆ -alkyl, unsubstituted or phenyl-substituted C₁ -C₈ -alkoxy, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, thienyl, C₁ -C₄ -alkylthienyl, pyridyl or C₁ -C₄ -alkylpyridyl,

L¹⁰ is phenyl, tolyl or pyridyl,

L¹¹ is trifluoromethyl, nitro, C₁ -C₆ -alkyl, phenyl, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio or C₁ -C₆ -dialkylamino,

L¹² is C₁ -C₆ -alkyl, phenyl, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio, 2-cyanoethylthio or 2-(C₁ -C₆ -alkoxycarbonyl)ethylthio,

L¹³ is hydrogen, nitro or halogen,

L¹⁴ is hydrogen, cyano, C₁ -C₈ -alkoxycarbonyl, nitro or halogen,

L¹⁵, L¹⁶ and L¹⁷ are independently of one another hydrogen, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, halogen, nitro, cyano, unsubstituted or phenoxy-substituted C₁ -C₈ -alkoxycarbonyl, C₁ -C₈ -alkylsulfonyl or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl, or L¹⁵ and L¹⁶ are together a radical of the formula CO--NW--CO, where W is C₁ -C₁₀ -alkyl with or without interruption by from 1 to 4 oxygen atoms in ether function and with or without substitution by hydroxyl,

L¹⁸ is hydrogen, methyl or chlorine, and

L¹⁹ is cyano or C₁ -C₈ -alkoxycarbonyl, and

K is a radical of the formula ##STR5## where Y¹ and Y² are independently of each other C₁ -C₁₀ -alkyl with or without substitution by cyano, hydroxyl, halogen, C₁ -C₄ -alkanoyloxy, C₁ -C₄ -alkoxycarbonyl, C₁ -C₄ -alkoxycarbonyloxy, whose alkyl chain may in each case be interrupted by an oxygen atom in ether function, or phenyl and with or without interruption by from 1 to 4 oxygen atoms in ether function, C₅ -C₇ -cycloalkyl, C₃ -C₄ -alkenyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, or Y¹ and Y² are together with the nitrogen atom joining them together a 5- or 6-membered saturated heterocyclic radical with or without further hetero atoms,

Y³ is C₃ -C₁₀ -alkyl, C₅ -C₇ -cycloalkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl or thienyl,

Y⁴ is hydrogen, C₁ -C₁₀ -alkyl with or without interruption by from 1 to 4 oxygen atoms in ether function, hydroxyl, C₁ -C₆ -alkoxy, in particular methoxy or ethoxy, C₁ -C₄ -alkylsulfonamido, mono- or di(C₁ -C₈ -alkyl)aminosulfonylamino or the radical --NHCOY⁸ or --NHCO₂ Y⁸, where Y⁸ is phenyl, benzyl, tolyl or C₁ -C₁₀ -alkyl with or without interruption by from 1 to 4 oxygen atoms in ether function,

Y⁵ is hydrogen, C₁ -C₆ -alkyl or C₁ -C₆ -alkoxy, and

Y⁶ and Y⁷ are independently of each other hydrogen, C₁ -C₁₀ -alkyl, with or without substitution by cyano, hydroxyl, halogen, C₁ -C₄ -alkanoyloxy, C₁ -C₄ -alkoxycarbonyl, C₁ -C₄ -alkoxycarbonyloxy, whose alkyl chain may in each case be interrupted by an oxygen atom in ether function, or phenyl and with or without interruption by from 1 to 4 oxygen atoms in ether function, C₅ -C₇ -cycloalkyl, C₃ -C₄ -alkenyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, or Y⁶ and Y⁷ are together with the nitrogen atom joining them together a 5- or 6-membered saturated heterocyclic radical with or without further hetero atoms,

and to a process for the thermal transfer of these dyes.

In the thermal transfer printing process, a transfer sheet which contains a thermally transferable dye in one or more binders with or without suitable auxiliaries on a support material is heated from the back with an energy source, for example with a thermal head or a laser, for short periods (duration: fractions of a second), causing the dye to migrate out of the transfer sheet and diffuse into the surface coating of a receiving medium. The essential advantage of this process is that the amount of dye to be transferred (and thus the color gradation) is easy to control by controlling the energy to be emitted by the energy source.

Generally, color recording is carried out using the three subtractive primaries of yellow, magenta and cyan (with or without black).

It is known to carry out the thermal transfer printing process with individual dyes or else with mixtures of dyes. However, it has been found that the dyes used frequently still have applications defects.

It is an object of the present invention to provide novel dye mixtures in the blue and red region which shall be advantageous for thermal transfer.

We have found that this object is achieved by the above-defined dye mixtures.

Any alkyl and alkenyl appearing in the abovementioned formulae may be straight-chain or branched.

In any substituted alkyl appearing in the abovementioned formulae the number of substituents is generally 1 or 2.

In any substituted phenyl, pyridyl or thienyl appearing in the abovementioned formulae the number of substituents is generally from 1 to 3, preferably 1 or 2.

B¹, B², L², L⁴, L⁵, L⁸, L⁹, L¹¹, L¹², L¹⁵, L¹⁶, L¹⁷, R¹, R², R⁴, R⁶, R⁷, Y¹, Y², Y⁴, Y⁵, Y⁶, Y⁷, Y⁸ and W are each for example methyl or ethyl.

R³ and Y³ as well as B¹, B², L², L⁴, L⁵, L⁸, L⁹, L¹¹, L¹², L¹⁵, L¹⁶, L¹⁷, R¹, R², R⁴, R⁶, R⁷, Y¹, Y², Y⁴, Y⁵, Y⁶, Y⁷, Y⁸ and W are each propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, tert-pentyl, hexyl or 2-methylpentyl.

B¹, B², R¹, R², R³, R⁶, R⁷, Y¹, Y², Y³, Y⁴, Y⁶, Y⁷, Y⁸ and W may each also be for example heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl or isodecyl (the designations isooctyl, isononyl and isodecyl are trivial names derived from the oxo process alcohols--cf. Ullmann's Encyclopedia of Industrial Chemistry, 5^(th) Edition, Vol. A 1, pages 290 to 293, and Vol. A 10, pages 284 and 285).

R¹, R², R³, R⁶, R⁷, Y¹, Y², Y³, Y⁶ and Y⁷ may each also be for example cyclopentyl, methylcyclopentyl, dimethylcyclopentyl, cyclohexyl, methylcyclohexyl or cycloheptyl.

R¹, R², R⁶, R⁷, Y¹, Y², Y⁴, Y⁶, Y⁷, Y⁸ and W may each also be for example 2-methoxyethyl, 2-ethoxyethyl, 2-propoxyethyl, 2-isopropoxyethyl, 2-butoxyethyl, 2- or 3-methoxypropyl, 2- or 3-ethoxypropyl, 2- or 3-propoxypropyl, 2- or 3-butoxypropyl, 2- or 4-methoxybutyl, 2- or 4-ethoxybutyl, 2- or 4-propoxybutyl, 2- or 4-butoxybutyl, 3,6-dioxaheptyl, 3,6-dioxaoctyl, 4,8-dioxanonyl, 3,7-dioxaoctyl, 3,7-dioxanonyl, 4,7-dioxaoctyl, 4,7-dioxanonyl, 4,8-dioxadecyl, 3,6,8-trioxadecyl, 3,6,9-trioxyundecyl, 3,6,9,12-tetraoxatridecyl or 3,6,9,12-tetraoxatetradecyl.

R¹, R², Y¹, Y², Y⁶ and Y⁷ may each also be for example 2-methoxycarbonylethyl, 2-ethoxycarbonylethyl, 2-propoxycarbonylethyl, 2-isopropoxycarbonylethyl, 2-butoxycarbonylethyl, 2- or 3-methoxycarbonylpropyl, 2- or 3-ethoxycarbonylpropyl, 2- or 3-propoxycarbonylpropyl, 2- or 3-butoxycarbonylpropyl, 2- or 4-methoxycarbonylbutyl, 2- or 4-ethoxycarbonylbutyl, 2- or 4-propoxycarbonylbutyl, 2- or 4-butoxycarbonylbutyl, 2-methoxycarbonyloxyethyl, 2-ethoxycarbonyloxyethyl, 2propoxycarbonyloxyethyl, 2-isopropoxycarbonyloxyethyl, 2-butoxycarbonyloxyethyl, 2- or 3-methoxycarbonyloxypropyl, 2- or 3-ethoxycarbonyloxypropyl, 2- or 3-propoxycarbonyloxypropyl, 2- or 3-butoxycarbonyloxypropyl, 2- or 4-methoxycarbonyloxybutyl, 2- or 4-ethoxycarbonyloxybutyl, 2- or 4-propoxycarbonyloxybutyl, 2- or 4-butoxycarbonyloxybutyl, prop-1-en-3-yl, but-2-en-4-yl or 2-methylprop-1-en-3-yl.

R⁶ and R⁷ may also be for example 2-benzyloxyethyl, 2-pyrazol-1-yl-ethyl, 2- or 3-benzyloxypropyl, 2- or 3-pyrazol-1-ylpropyl, 2- or 4-benzyloxybutyl, 2- or 4-pyrazol-1-ylbutyl, 2-phenoxyethyl, 2- or 3-phenoxypropyl, 2- or 4-phenoxybutyl, 2-cyclohexyloxyethyl, 2- or 3-cyclohexyloxypropyl, or 2- or 4-cyclohexyloxybutyl.

Y¹, Y², Y⁶ and Y⁷ may each also be for example 2-cyanoethyl, 2- or 3-cyanopropyl, 2- or 4-cyanobutyl, 2-hydroxyethyl, 2- or 3-hydroxypropyl, 2- or 4-hydroxybutyl, 2-chloroethyl, 2- or 3-chloropropyl, 2- or 4-chlorobutyl, 2-acetyloxyethyl, 2- or 3-acetyloxypropyl, 2- or 4-acetyloxybutyl, 2-propionyloxyethyl, 2- or 3-propionyloxypropyl or 2- or 4-propionyloxybutyl.

L⁹, R¹, R², R⁶, R⁷, Y¹, Y², Y⁶ and Y⁷ may each also be for example benzyl or 1- or 2-phenylethyl.

B¹, B², L², L⁸, L⁹, R¹, R², R³, R⁴, R⁶, R⁷, Y¹, Y², Y³, Y⁶, and Y⁷ may each also be for example phenyl, 2-, 3- or 4-methylphenyl, 2-, 3- or 4-ethylphenyl, 2-, 3- or 4-propylphenyl, 2-, 3- or 4-isopropylphenyl, 2-, 3- or 4-butylphenyl, 2,3-,2,4- or 2,6-dimethylphenyl, 2-, 3- or 4-methoxyphenyl, 2-, 3-, or 4-ethoxyphenyl, 2,3-, 2,4- or 2,6-dimethoxyphenyl, 2-, 3- or 4-fluorophenyl 2-, 3- or 4-chlorophenyl, 2-, 3- or 4-bromophenyl or 2-, 3- or 4-nitrophenyl.

R⁵ is for example mono- or dimethylcarbamoyl, mono- or diethylcarbamoyl, mono- or dipropylcarbamoyl, mono- or diisopropylcarbamoyl, mono- or dibutylcarbamoyl, mono- or dipentylcarbamoyl, mono- or dihexylcarbamoyl, mono- or diheptylcarbamoyl, mono- or dioctylcarbamoyl, mono- or bis(2-ethylhexyl)carbamoyl or N-methyl-N-ethylcarbamoyl. L², L⁸, L⁹ and L¹¹ may each also be for example methylthio, ethylthio, propylthio, isopropylthio, butylthio, isobutylthio, pentylthio, hexylthio, heptylthio, octylthio, 2-ethylhexylthio, benzylthio or 1- or 2-phenylethylthio.

L² and L⁸ may each also be for example phenylthio, 2-methylphenylthio, 2-methoxyphenylthio or 2-chlorophenylthio.

L², L⁸, L⁹, L¹⁵, L¹⁶, L¹⁷, Y⁴ and Y⁵ may each also be for example methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, pentyloxy, isopentyloxy, neopentyloxy, tert-pentyloxy, hexyloxy or 2-methylpentyloxy.

L², L⁸ and L⁹ may each also be for example benzyloxy or 1- or 2-phenylethoxy.

L⁶ as well as L², L⁸, L¹³, L¹⁴, L¹⁵, L¹⁶ and L¹⁷ is for example fluorine, chlorine or bromine.

L⁷ and L¹ as well as B¹, B², L², L⁸, L¹⁵, L¹⁶ and L¹⁷, are each for example methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, isobutylsulfonyl sec-butylsulfonyl, pentylsulfonyl, isopentylsulfonyl, neopentylsulfonyl, hexylsulfonyl, heptylsulfonyl, octylsulfonyl, 2-ethylhexylsulfonyl, phenylsulfonyl, 2-methylphenylsulfonyl, 2-methoxyphenylsulfonyl or 2-chlorophenylsulfonyl.

L³ and L⁹ as well as L¹, L⁶, L⁷, L⁸, L¹⁴, L¹⁵, L¹⁶, L¹⁷ and R⁵ are each for example methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, pentyloxycarbonyl, isopentyloxycarbonyl, neopentyloxycarbonyl, hexyloxycarbonyl, heptyloxycarbonyl, octyloxycarbonyl, isooctyloxycarbonyl or 2-ethylhexyloxycarbonyl.

L¹⁵, L¹⁶ and L¹⁷ may each also be for example 2-phenoxyethoxycarbonyl, 2- or 3-phenoxypropobutoxycarbonyl or 2- or 4- phenoxybutocarbonyl.

L² and L⁸ may each also be for example 2-methoxyethoxy, 2-ethoxyethoxy, 2- or 3-methoxypropoxy, 2- or 3-ethoxypropoxy, 2- or 4-methoxybutoxy, 2- or 4-ethoxybutoxy, 5-methoxypentyloxy, 5-ethoxypentyloxy, 6-methoxyhexyloxy or 6-ethoxyhexyloxy.

L¹¹ may also be for example dimethylamino, diethylamino, dipropylamino, diisopropylamino, dibutylamino, dipentylamino, dihexylamino or N-methyl-N-ethylamino.

L¹² may also be for example 2-methoxycarbonylethylthio or 2-ethoxycarbonylethylthio.

L⁹ may also be for example 2- or 3-methylthienyl or 2-, 3- or 4-methylpyridyl.

B¹, B², L¹, L⁶ and L⁷ may each also be for example formyl, acetyl, propionyl, butyryl, pentanoyl or hexanoyl.

B¹ and B² may each also be for example heptanoyl, octanoyl, 2-ethylhexanoyl, isooctanoyl, nonanoyl, isononanoyl, benzoyl, 2-, 3- or 4-methylbenzoyl or 2-, 3- or 4-methoxybenzoyl.

Y⁴ may also be for example acetylamino, propionylamino, methoxyacetylamino, benzoylamino, methoxycarbonylamino, ethoxycarbonylamino, methylsulfonylamino, ethylsulfonylamino, propylsulfonylamino, isopropylsulfonylamino, butylsulfonylamino, mono- or dimethylaminosulfonylamino, mono- or diethylaminosulfonylamino, mono- or dipropylaminosulfonylamino, mono- or diisopropylamino-sulfonylamino, mono- or dibutylaminosulfonylamino or (N-methyl-N-ethylaminosulfonyl)amino.

In a --CH═T radical L¹ and L⁷ where T is derived from an acidic-CH compound H₂ T, said acidic-CH compounds H₂ T can be for example compounds of the formula ##STR6## where Z¹ is cyano, nitro, C₁ -C₄ -alkanoyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted benzoyl, C₁ -C₄ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl, C₁ -C₄ -alkoxycarbonyl, C₃ -C₄ -alkenyloxycarbonyl, phenoxycarbonyl, carbamoyl, mono- or di(C₁ -C₄ -alkyl)carbamoyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylcarbamoyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, benzothiazol-2-yl, benzimidazol-2-yl, 5-phenyl-1,3,4-thiadiazol-2-yl or 2-hydroxyquinoxalin-3-yl,

Z² is C₁ -C₆ -alkyl, C₁ -C⁶ -alkoxy or C₃ -C₄ -alkenyloxy,

Z³ is C₁ -C₄ -alkoxycarbonyl, C₃ -C₄ -alkenyloxycarbonyl, phenylcarbamoyl or benzimidazol-2-yl,

Z⁴ is cyano, C₁ -C₄ -alkoxycarbonyl or C₃ -C₄ -alkenyloxycarbonyl,

Z⁵ is hydrogen or C₁ -C₆ -alkyl,

Z⁶ is hydrogen, C₁ -C₆ -alkyl or phenyl, and

Z⁷ is C₁ -C₆ -alkyl.

Attention is drawn to the radical derived from compounds of the formula Va, Vb or Vc where Z¹ is cyano, C₁ -C₄ -alkanoyl, C₁ -C₄ -alkoxycarbonyl or C₃ -C₄ -alkenyloxycarbonyl, Z² is C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy or C₃ -C₄ -alkenyloxy, Z³ is C₁ -C₄ -alkoxycarbonyl or C₃ -C₄ -alkenyloxycarbonyl and Z⁴ is cyano.

Particular attention is drawn to the radical derived from compounds of the formula Va, Vb or Vc where Z¹ is cyano, C₁ -C₄ -alkoxycarbonyl or C₃ -C₄ -alkenyloxycarbonyl, Z² is C₁ -C₄ -alkoxy or C₂ -C₄ -alkenyloxy, Z³ is C₁ -C₄ -alkoxycarbonyl or C3-C₄ -alkenyloxycarbonyl and Z⁴ is cyano.

R¹ and R², Y¹ and Y² or Y⁶ and Y⁷ each combined with the nitrogen atom joining them together into a 5- or 6-membered saturated heterocyclic radical with or without further hetero atoms may be for example pyrrolidinyl, piperidinyl, morpholinyl, thiomorpholinyl, thiomorpholinyl-S,S-dioxide, piperazinyl or N-(C₁ -C₄ -alkyl) piperazinyl, such as N-methyl- or N-ethyl-piperazinyl.

When R¹ and R² in the formula I are each C₁ -C₁₀ -alkyl, or when one of R¹ and R² is C₁ -C₁₀ -alkyl and the other is C₅ -C₇ -cycloalkyl, then preference is given to those pyridone dyes in the dye mixtures in which the sum of the carbon atoms present in the two radicals R¹ and R² is at least 7, preferably at least 8.

Preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where X is CH.

Preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R⁴ is methyl.

Preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R⁵ is cyano.

Preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R³ is C₃ -C₁₀ -alkyl, especially C₃ -C₈ -alkyl, attention being drawn to branched alkyl in each case, phenyl or thienyl.

Preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R⁶ is C₁ -C₈ -alkyl, cyclopentyl, cyclohexyl or unsubstituted or C₁ -C₄ -alkyl- or C₁ -C₄ -alkoxy-substituted phenyl.

Preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R⁷ is C₁ -C₈ -alkyl or unsubstituted or C₁ -C₄ -alkyl- or C₁ -C₄ -alkoxy-substituted phenyl.

Preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R¹ and R² are independently of each other C₁ -C₈ -alkyl, which may be unsubstituted or C₁ -C₄ -alkoxy-, C₁ -C₄ -alkoxycarbonyl- or phenyl-substituted, cyclopentyl, cyclohexyl or prop-1-en-3-yl.

Particular preference is given to dye mixtures which include one or more pyridone dyes of the formula I where R³ is branched C₃ -C₆ -alkyl, especially isopropyl, isobutyl or tert-butyl. tert-Butyl is particularly preferred.

Particular preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R⁶ is C₄ -C₈ -alkyl or cyclohexyl.

Particular preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R⁷ is C₁ -C₈ -alkyl.

Particular preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where R¹ and R² are independently of each other C₄ -C₈ -alkyl, C₁ -C₄ -alkoxy-C₂ -C₄ -alkyl, C₁ -C₄ -alkoxycarbonyl-C₂ -C₄ -alkyl, benzyl or prop-1-en-3-yl or where one of R¹ and R² is C₁ -C₄ -alkyl and the other is cyclohexyl.

Particular preference is further given to dye mixtures which include one or more pyridone dyes of the formula I where M is a radical of the formula ##STR7## where R⁴, R⁵, R⁶ and X are each as defined above.

Very particular preference is given to dye mixtures which include one or more pyridone dyes of the formula I where R¹ and R² are independently of each other C₄ -C₈ -alkyl, benzyl or prop-1-en-3-yl.

Preference is further given to dye mixtures which include one or more azo dyes of the formula II where D is a radical of the formula IIIb, IIId, IIIe or IIIq.

Particular preference is further given to dye mixtures which include one or more azo dyes of the formula II where D is a radical of the formula IIlb, IIId, IIIe or IIIq where

L¹ is nitro, cyano, formyl or a radical of the formula --CH═T, where T is as defined above,

L² is hydrogen, C₁ -C₆ -alkyl or halogen,

L³ is cyano, C₁ -C₆ -alkoxycarbonyl or nitro,

L⁶ is cyano or nitro,

L⁷ is nitro, cyano, formyl, C₁ -C₆ -alkoxycarbonyl or a radical of the formula --CH═T, where T is as defined above,

L⁸ is C₁ -C₆ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, cyano, halogen or C₁ -C₆ -alkoxycarbonyl,

L⁹ is unsubstituted or phenyl-substituted C₁ -C₆ -alkyl, unsubstituted or phenyl-substituted C₁ -C₆ -alkylthio or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl or thienyl and

L¹⁵, L¹⁶ and L¹⁷ are independently of one another hydrogen, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, nitro, cyano or unsubstituted or phenoxy-substituted C₁ -C₆ -alkoxycarbonyl or L¹⁵ and L¹⁶ are together a radical of the formula CO--NW--CO, where W is as defined above.

Of particular importance are dye mixtures which include one or more azo dyes of the formula II where D is a radical of the formula IIIe.

Preference is further given to dye mixtures which include one or more azo dyes of the formula II where Y¹, Y², Y⁶ and Y⁷ are independently of one another C₁ -C₆ -alkyl with or without substitution by hydroxyl, C₁ -C₄ -alkanoyloxy, C₁ -C₄ -alkoxycarbonyl, C₁ -C₄ -alkoxycarbonyloxy or phenyl and with or without interruption by 1 or 2 oxygen atoms in ether function.

Preference is further given to dye mixtures which include one or more azo dyes of the formula II where Y³ is branched C₃ -C₁₀ -alkyl.

Preference is further given to dye mixtures which include one or more azo dyes of the formula II where Y⁵ is hydrogen, C₁ -C₄ -alkyl, methoxy, ethoxy or C₁ -C₆ -alkanoylamino.

The dye mixtures of the present invention include typically from 5 to 95% by weight, preferably from 20 to 80% by weight, especially from 40 to 60% by weight, based on the weight of the dye mixture, of one or more pyridone dyes of the formula I and also from 5 to 95% by weight, preferably from 20 to 80% by weight, especially from 40 to 60% by weight, based on the weight of the dye mixture, of one or more azo dyes of the formula II.

The novel dye mixtures are obtainable in a conventional manner, for example by blending the individual dyes in the abovementioned weight ratio.

The pyridone dyes of the formula I are known per se and described for example in U.S. Pat. No. 5,079,365, in the prior patent applications PCT/EP 94/04114, PCT/EP 95/00564 or in the prior German patent application 19504943.8 or are obtainable by the methods mentioned therein. The thermal transfer of such dyes is described for example in the prior European patent application No. 95106055.7.

The azo dyes of the formula II are likewise known per se and described for example in the prior German patent application P 44 26 023.7. Those azo dyes with a coupling component of the aniline series can likewise be obtained by the methods mentioned therein or else as described in U.S. Pat. No. 5,283,326.

The dye mixtures of the present invention are notable for advantageous application properties. They display high solubility in the ink ribbon (good compatibility with the binder), high stability in the printing ink, good transferability, high image stability (i.e. good light fastness and also good stability to environmental effects, e.g. moisture, temperature or chemicals) and ensure a flexible coloristic adaptation to the other subtractive primary colors, which gives rise to high quality color spaces. In addition, the dye mixtures of the present invention make it possible to produce good blacks.

Attention is also drawn to the spectrally uniform decrease in the individual components on irradiation; that is, the individual dye having the lower light fastness does not usually decrease preferentially.

The present invention further provides a process for transferring dyes from a transfer to a plastic-coated paper by diffusion or sublimation with the aid of an energy source, which comprises using a transfer on which there is an above-defined dye mixture.

To make the transfers required for the process of the present invention, the dye mixtures are incorporated in a suitable organic solvent or a mixture of solvents with one or more binders with or without auxiliaries to form a printing ink. This printing ink preferably contains the dyes in a molecularly disperse, i.e. dissolved, form. The printing ink can be applied to the inert support by means of a doctor blade and air dried. Suitable organic solvents for the dye mixtures include for example those in which the solubility of the dye mixtures at a temperature of 20° C. is greater than 1% by weight, preferably greater than 5% by weight.

Examples are ethanol, propanol, isobutanol, tetrahydrofuran, methylene chloride, methyl ethyl ketone, cyclopentanone, cyclohexanone, toluene, chlorobenzene or mixtures thereof.

Suitable binders include all resins or polymer materials which are soluble in organic solvents and which are capable of binding the dye mixtures to the inert support sufficiently firmly as to prevent rubbing off. Preference is given to those binders which, after the air drying of the printing ink, include the dye mixture in the form of a clear, transparent film without any visible crystallization of the dye mixture.

Such binders are mentioned for example in U.S. Pat. No. 5,132,438 or in the pertinent patent applications cited therein. Also suitable are saturated linear polyesters.

Preferred binders include ethylcellulose, ethylhydroxyethylcellulose, polyvinyl butyral, polyvinyl acetate, cellulose propionate or saturated linear polyesters.

The weight ratio of binder: dye mixture generally ranges from 1:1 to 10:1.

Suitable auxiliaries include for example release agents as mentioned in U.S. Pat. No. 5,132,438 or the pertinent patent applications cited therein. Also suitable are especially organic additives which prevent the crystallizing out of the transfer dyes in the course of storage or on heating of the color ribbon, for example cholesterol or vanillin.

Suitable inert supports are described for example in U.S. Pat. No. 5,132,438 or in the pertinent patent applications cited therein. The thickness of the support generally ranges from 3 to 30 μm, preferably from 5 to 10 μm.

Suitable dye receiver layers include in principle all thermally stable plastics layers with affinity for the dyes to be transferred, for example modified polycarbonates or polyesters. Further details can be found for example in U.S. Pat. No. 5,132,438 or the pertinent patent applications cited therein.

The transfer is effected by means of an energy source, for example by means of a laser or a thermal head, for which the latter has to be heatable to a temperature of ≧300 ° C. so that the transfer of the dye can take place within the time range t: 0<t<15 msec. The dye migrates out of the transfer sheet and diffuses into the surface coating of the receiving medium.

The dye mixtures of the present invention are also advantageously suitable for dyeing or printing synthetic materials, for example polyesters, polyamides or polycarbonates. Particularly suitable are textile materials such as fibers, yarns, threads, knits, wovens or nonwovens composed of polyester, modified polyester, eg. anionically modified polyester, or, blend fabrics of polyesters with cellulose, cotton, viscose or wool. The dyeing and printing conditions are known per se. The dyes of this invention can also be used for dyeing keratinous fibers, for example in hair dyeing or for dyeing furs.

The novel dye mixtures are also advantageously suitable for producing color filters as described for example in EP-A-399 473.

Finally, they can also be used with advantage as colorants for making toners for electrophotography.

The Examples which follow illustrate the invention.

Tables 1 to 5 below list the individual dyes used as blending partners.

                  TABLE 1                                                          ______________________________________                                          ##STR8##                                                                      Dye                                                                            No.     NR.sup.1 R.sup.2                                                                             R.sup.3   R.sup.6                                        ______________________________________                                         1       N(C.sub.4 H.sub.9).sub.2                                                                     C(CH.sub.3).sub.3                                                                        CH.sub.3                                       2       N(C.sub.4 H.sub.9).sub.2                                                                     C(CH.sub.3).sub.3                                                                        C.sub.4 H.sub.9                                3       N(C.sub.4 H.sub.9).sub.2                                                                     C(CH.sub.3).sub.3                                                                        C.sub.2 H.sub.4 OCH.sub.3                      4       N(C.sub.4 H.sub.9).sub.2                                                                     C(CH.sub.3).sub.3                                                                        C.sub.3 H.sub.6 OCH.sub.3                      5       N CH(CH.sub.3)C.sub.2 H.sub.5 !.sub.2                                                        C(CH.sub.3).sub.3                                                                        CH.sub.3                                       6       N CH(CH.sub.3)C.sub.2 H.sub.5 !.sub.2                                                        C(CH.sub.3).sub.3                                                                        C.sub.4 H.sub.9                                7       N(C.sub.2 H.sub.5).sub.2                                                                     C(CH.sub.3).sub.3                                                                        CH(CH.sub.3)C.sub.2 H.sub.5                    8       N(C.sub.2 H.sub.5).sub.2                                                                     C(CH.sub.3).sub.3                                                                        CH.sub.3                                       9       N(C.sub.2 H.sub.5).sub.2                                                                     C(CH.sub.3).sub.3                                                                        C.sub.4 H.sub.9                                10      N(C.sub.4 H.sub.9).sub.2                                                                     C(CH.sub.3).sub.3                                                                        C.sub.2 H.sub.5                                11      N(CH.sub.3).sub.2                                                                            (C(CH.sub.3).sub.3                                                                       C.sub.3 H.sub.6 OC.sub.2 H.sub.4 OC.sub.2                                      H.sub.5                                        12      N(CH.sub.3).sub.2                                                                            (C(CH.sub.3).sub.3                                                                       C.sub.4 H.sub.9                                ______________________________________                                    

                                      TABLE 2                                      __________________________________________________________________________     DNNK                                                                           Dye No.                                                                             D               K                                                         __________________________________________________________________________     13                                                                                   ##STR9##                                                                                       ##STR10##                                                14                                                                                   ##STR11##                                                                                      ##STR12##                                                15                                                                                   ##STR13##                                                                                      ##STR14##                                                16                                                                                   ##STR15##                                                                                      ##STR16##                                                17                                                                                   ##STR17##                                                                                      ##STR18##                                                18                                                                                   ##STR19##                                                                                      ##STR20##                                                19                                                                                   ##STR21##                                                                                      ##STR22##                                                20                                                                                   ##STR23##                                                                                      ##STR24##                                                21                                                                                   ##STR25##                                                                                      ##STR26##                                                22                                                                                   ##STR27##                                                                                      ##STR28##                                                23                                                                                   ##STR29##                                                                                      ##STR30##                                                24                                                                                   ##STR31##                                                                                      ##STR32##                                                25                                                                                   ##STR33##                                                                                      ##STR34##                                                26                                                                                   ##STR35##                                                                                      ##STR36##                                                27                                                                                   ##STR37##                                                                                      ##STR38##                                                28                                                                                   ##STR39##                                                                                      ##STR40##                                                29                                                                                   ##STR41##                                                                                      ##STR42##                                                30                                                                                   ##STR43##                                                                                      ##STR44##                                                31                                                                                   ##STR45##                                                                                      ##STR46##                                                32                                                                                   ##STR47##                                                                                      ##STR48##                                                33                                                                                   ##STR49##                                                                                      ##STR50##                                                34                                                                                   ##STR51##                                                                                      ##STR52##                                                35                                                                                   ##STR53##                                                                                      ##STR54##                                                36                                                                                   ##STR55##                                                                                      ##STR56##                                                37                                                                                   ##STR57##                                                                                      ##STR58##                                                38                                                                                   ##STR59##                                                                                      ##STR60##                                                39                                                                                   ##STR61##                                                                                      ##STR62##                                                40                                                                                   ##STR63##                                                                                      ##STR64##                                                41                                                                                   ##STR65##                                                                                      ##STR66##                                                42                                                                                   ##STR67##                                                                                      ##STR68##                                                43                                                                                   ##STR69##                                                                                      ##STR70##                                                44                                                                                   ##STR71##                                                                                      ##STR72##                                                45                                                                                   ##STR73##                                                                                      ##STR74##                                                46                                                                                   ##STR75##                                                                                      ##STR76##                                                47                                                                                   ##STR77##                                                                                      ##STR78##                                                48                                                                                   ##STR79##                                                                                      ##STR80##                                                49                                                                                   ##STR81##                                                                                      ##STR82##                                                __________________________________________________________________________

                                      TABLE 3                                      __________________________________________________________________________      ##STR83##                                                                     Dye No.                                                                              NR.sup.1 R.sup.2                                                                         R.sup.3     R.sup.6                                            __________________________________________________________________________     50    N(C.sub.2 H.sub.5).sub.2                                                                  ##STR84##  C.sub.6 H.sub.13                                   51    N(C.sub.4 H.sub.9).sub.2                                                                  ##STR85##                                                                                  ##STR86##                                         52    N CH.sub.2 CH(CH.sub.3).sub.2 !.sub.2                                                     ##STR87##                                                                                  ##STR88##                                         53    N(C.sub.2 H.sub.5).sub.2                                                                  ##STR89##  C.sub.4 H.sub.9                                    54    N(CH.sub.2CHCH.sub.2).sub.2                                                               ##STR90##  CH.sub.3                                           55    N(CH.sub.2CHCH.sub.2).sub.2                                                               ##STR91##  C.sub.4 H.sub.9                                    56    N(C.sub.4 H.sub.9).sub.2                                                                  ##STR92##  CH.sub.3                                           57    N(C.sub.2 H.sub.5).sub.2                                                                  ##STR93##  C.sub.4 H.sub.9                                    58    N(C.sub.4 H.sub.9).sub.2                                                                  ##STR94##  C.sub.6 H.sub.13                                   59    N(C.sub.4 H.sub.9).sub.2                                                                  ##STR95##  C.sub.6 H.sub.13                                   60                                                                                    ##STR96##                                                                                ##STR97##  C.sub.6 H.sub.13                                   61    N(C.sub.4 H.sub.9).sub.2                                                                  ##STR98##  CH.sub.3                                           62    N(C.sub.4 H.sub.9).sub.2                                                                  ##STR99##                                                                                  ##STR100##                                        63    N(C.sub.4 H.sub.9).sub.2                                                                  ##STR101##                                                                                 ##STR102##                                        64                                                                                    ##STR103##                                                                               ##STR104##                                                                                 ##STR105##                                        65                                                                                    ##STR106##                                                                               ##STR107## C.sub.4 H.sub.9                                    66                                                                                    ##STR108##                                                                               ##STR109## C.sub.6 H.sub.13                                   67    N(C.sub.2 H.sub.4 OCH.sub.3).sub.2                                                        ##STR110## NHCOCH(C.sub.2 H.sub.5)C.sub.4 H.sub.9             68    N(C.sub.2 H.sub.4 OCH.sub.3).sub.2                                                        ##STR111## C.sub.6 H.sub.13                                   69    N(C.sub.2 H.sub.4 OCH.sub.3).sub.2                                                        ##STR112## CH.sub.3                                           70                                                                                    ##STR113##                                                                               ##STR114## H                                                  71    N (C.sub.2 H.sub.4 O).sub.3 CH.sub.3 !.sub.2                                              ##STR115## CH.sub.3                                           72    N (C.sub.2 H.sub.4 O).sub.3 CH.sub.3 !.sub.2                                              ##STR116## C.sub.4 H.sub.9                                    73    N (C.sub.2 H.sub.4 O).sub.3 CH.sub.3 !.sub.2                                              ##STR117## C.sub.6 H.sub.13                                   74    N (C.sub.2 H.sub.4 O).sub.3 CH.sub.3 !.sub.2                                              ##STR118## H                                                  75    N(C.sub.4 H.sub.9).sub.2                                                                  ##STR119## C.sub.6 H.sub.13                                   __________________________________________________________________________

                  TABLE 4                                                          ______________________________________                                          ##STR120##                                                                    Dye                                                                            No.  NR.sup.1 R.sup.2                                                                               R.sup.3       R.sup.6                                     ______________________________________                                         76   N(C.sub.4 H.sub.9).sub.2                                                                        ##STR121##   C.sub.6 H.sub.13                            77   N(C.sub.4 H.sub.9).sub.2                                                                        ##STR122##   C.sub.3 H.sub.6 OCH.sub.3                   78   N CH.sub.2 CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9 !.sub.2                                           ##STR123##   C.sub.6 H.sub.13                            79                                                                                   ##STR124##                                                                                     ##STR125##   CH.sub.3                                    ______________________________________                                    

                                      TABLE 5                                      __________________________________________________________________________     DNNK                                                                           Dye No.                                                                             D                   K                                                     __________________________________________________________________________     80                                                                                   ##STR126##                                                                                         ##STR127##                                           81                                                                                   ##STR128##                                                                                         ##STR129##                                           82                                                                                   ##STR130##                                                                                         ##STR131##                                           83                                                                                   ##STR132##                                                                                         ##STR133##                                           84                                                                                   ##STR134##                                                                                         ##STR135##                                           85                                                                                   ##STR136##                                                                                         ##STR137##                                           86                                                                                   ##STR138##                                                                                         ##STR139##                                           87                                                                                   ##STR140##                                                                                         ##STR141##                                           88                                                                                   ##STR142##                                                                                         ##STR143##                                           89                                                                                   ##STR144##                                                                                         ##STR145##                                           90                                                                                   ##STR146##                                                                                         ##STR147##                                           91                                                                                   ##STR148##                                                                                         ##STR149##                                           92                                                                                   ##STR150##                                                                                         ##STR151##                                           93                                                                                   ##STR152##                                                                                         ##STR153##                                           94                                                                                   ##STR154##                                                                                         ##STR155##                                           95                                                                                   ##STR156##                                                                                         ##STR157##                                           96                                                                                   ##STR158##                                                                                         ##STR159##                                           97                                                                                   ##STR160##                                                                                         ##STR161##                                           98                                                                                   ##STR162##                                                                                         ##STR163##                                           99                                                                                   ##STR164##                                                                                         ##STR165##                                           100                                                                                  ##STR166##                                                                                         ##STR167##                                           101                                                                                  ##STR168##                                                                                         ##STR169##                                           __________________________________________________________________________

                  TABLE 6                                                          ______________________________________                                          ##STR170##                                                                    Dye No.                                                                               NR.sup.1 R.sup.2                                                                            R.sup.3     R.sup.7                                        ______________________________________                                         102                                                                                    ##STR171##                                                                                  ##STR172## CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9             103                                                                                    ##STR173##  C(CH.sub.3).sub.3                                                                          CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9             104    N(C.sub.2 H.sub.4 OCH.sub.3).sub.2                                                           ##STR174## CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9             105    N(CH.sub.2 C.sub.6 H.sub.5).sub.2                                                            ##STR175## CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9             106    N(C.sub.2 H.sub.5).sub.2                                                                    (C(CH.sub.3).sub.3                                                                         CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9             107    N(C.sub.4 H.sub.9).sub.2                                                                     ##STR176## CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9             108    N CH(CH.sub.3).sub.2 !.sub.2                                                                 ##STR177## CH(C.sub.2 H.sub.5)C.sub.4 H.sub.9             ______________________________________                                    

Procedure for thermal transfer:

a) 10 g of dye mixture are stirred, if necessary with brief heating to 80°-90° C., into 100 g of a 10% strength by weight solution of a binder based on polyvinyl butyral in 4.5:2:2 v/v/v methyl ethyl ketone/toluene/cyclohexanone.

The mixture is applied with a 10 μm doctor blade to a 6 μm thick polyester film which has a suitable slipping layer on the back and is blown dry with a hair dryer in the course of 1 minute. Before the color ribbon can be printed, it has to be air dried for at least a further 24 hours, since residual solvent can impair the printing process.

b) The color ribbons are printed on an experimental computer-controlled apparatus equipped with a commercial thermal printing head onto commercial color videoprint paper (Hitachi).

The voltage is altered to control the energy emitted by the thermal printing head, the length of a pulse having been set to 7 ms and only one pulse being emitted at a time. The emitted energy level ranges from 0.5 to 2.0 mJ/dot.

Since the depth of the color is directly proportional to the supplied energy, it is possible to use a color wedge for spectroscopic evaluation.

The depth of the color is plotted against the supplied energy per heating element to determine the Q* value (=energy in mJ for the absorbance value of 1) and the gradient m in 1/mJ.

The results obtained are shown together with the λ_(max) values (measured on the videoprint paper) below in Table 7.

Table 7 also lists the light fastness (LF) values of some dye mixtures. The value reported is the number of hours of irradiation after which 20% of the original dye quantity was destroyed.

                  TABLE 7                                                          ______________________________________                                         Mixture  Weight    λ.sub.max                                                                      LF     Q*    m*                                      of dyes  ratio      nm!    h!     mJ/dot!                                                                              1/mJ!                                  ______________________________________                                         1/30     1:1                     0,74  3,58                                    1/15     1:1       537    18     0,74  3,98                                    1/14     1:1       537    12     0,75  4,74                                    1/22     1:1       535    27     0,76  4,01                                    1/17     1:1       537    23     0,78  3,62                                    1/24     1:1       537    22     0,78  3,77                                    1/28     1:1       537    20     0,78  3,17                                    1/20     1:1       537    12     0,79  4,23                                    1/21     1:1       537    15     0,79  3,55                                    1/13     1:1       537    18     0,80  3,35                                    1/25     1:1       537    16     0,80  3,18                                    1/16     1:1       535    15     0,81  3,44                                    1/18     1:1       534    21     0,81  2,97                                    1/19     1:1       537    23     0,81  3,57                                    1/23     1:1       537    36     0,81  2,76                                    1/26     1:1       536           0,83  3,70                                    1/47     1:1       537    20     0,78  3,17                                    1/48     1:1       534           0,83  3,42                                    1/27     1:1       536           0,84  3,37                                     1/101   1:1       537           0,84  2,85                                    1/85     1:1       537           0,88  2,71                                    1/49     1:1       534           0,94  2,79                                    2/31     1:1                     0,82  3,76                                    2/26     1:1       535           0,89  3,01                                    2/49     1:1       536           0,94  2,75                                    3/14     1:1       537    18     0,79  4,05                                    3/15     1:1       537    19     0,79  4,09                                    3/28     1:1       537    19     0,79  3,62                                    3/22     1:1       537    26     0,81  3,75                                    3/17     1:1       537    31     0,82  3,42                                    3/24     1:1       537    17     0,82  3,77                                    3/25     1:1       537    31     0,82  3,61                                    3/26     1:1       537           0,82  3,39                                    3/13     1:1       537    22     0,83  3,47                                    3/20     1:1       537    16     0,83  4,06                                    3/21     1:1       537    16     0,83  3,31                                    3/16     1:1       537    24     0,85  3,21                                    3/18     1:1       534    24     0,85  3,18                                    3/49     1:1       535           0,86  2,46                                    3/27     1:1       537           0,87  2,77                                    3/85     1:1       537           0,88  2,76                                    3/19     1:1       537    18     0,88  2,79                                     3/101             537           0,88  2,80                                    3/23     1:1              26                                                   3/47     1:1       537    19     0,79  3,62                                    4/14     1:1       537    15     0,75  4,16                                    4/15     1:1       537    24     0,76  3,98                                    4/22     1:1       537    21     0,77  3,92                                    4/24     1:1       537    22     0,79  3,82                                    4/25     1:1       536    48     0,79  3,82                                    4/28     1:1       536    23     0,79  3,79                                    4/17     1:1       534    20     0,80  3,48                                    4/20     1:1       537    12     0,80  3,12                                    4/21     1:1       537    15     0,80  3,57                                    4/13     1:1       537    27     0,81  3,39                                    4/19     1:1       537    15     0,82  3,79                                    4/18     1:1       535    18     0,83  3,25                                    4/16     1:1       537    20     0,84  3,26                                    4/26     1:1       537           0,84  3,00                                    4/23     1:1       538    26     0,86  2,86                                    4/27     1:1       537           0,87  2,81                                    4/47     1:1       536    23     0,79  3,79                                     4/101   1:1       534           0,88  2,90                                    4/48     1:1       537           0,89  3,06                                    4/85     1:1       537           0,91  2,60                                    5/14     1:1       537    23     0,75  4,11                                    5/15     1:1       538    23     0,75  4,23                                    5/29     1:1       537    17     0,77  3,49                                    5/28     1:1       539    31     0,78  3,01                                    5/20     1:1       537    24     0,79  3,77                                    5/22     1:1       537    32     0,79  4,02                                    5/17     1:1       539    39     0,81  3,31                                    5/21     1:1       537    22     0,81  3,31                                    5/24     1:1       538    19     0,81  3,56                                    5/16     1:1       537    30     0,82  3,27                                    5/25     1:1       537    26     0,82  3,27                                    5/13     1:1       538    24     0,83  3,61                                    5/18     1:1       537    37     0,84  3,31                                    5/27     1:1       537           0,84  2,99                                    5/48     1:1       537           0,84  3,46                                    5/19     1:1       537    33     0,85  3,02                                    5/26     1:1       538           0,85  3,02                                    5/45     1:1                     0,79  3,96                                    5/47     1:1       536    23     0,79  3,79                                     5/101   1:1       538           0,88  2,80                                    5/49     1:1       537           0,89  2,77                                    5/23     1:1       539    33     0,92  2,57                                    5/85     1:1       539           0,94  2,43                                    6/14     1:1       537    26     0,74  4,80                                    6/15     1:1       537    31     0,75  4,44                                    6/13     1:1       538    19     0,80  3,95                                    6/49     1:1       537           0,81  2,80                                    6/26     1:1       539           0,83  3,25                                    6/23     1:1       539    35     0,87  2,88                                     6/101   1:1       538           0,88  2,67                                    6/27     1:1       537           0,91  2,49                                    6/85     1:1       537           0,94  2,30                                    7/29     1:1       536    13     0,78  3,38                                    7/14     1:1       534    20     0,78  4,12                                    7/15     1:1       534    24     0,79  3,69                                    7/23     1:1       534    30     0,80  3,34                                    7/22     1:1       534    23     0,81  3,64                                    7/26     1:1       533           0,81  3,35                                    7/28     1:1       535    24     0,81  3,52                                    7/20     1:1       536    16     0,82  3,33                                    7/24     1:1       534    30     0,82  2,87                                    7/47     1:1       535    24     0,81  3,52                                    7/25     1:1       533    25     0,82  3,45                                    7/48     1:1       533           0,82  3,25                                    7/17     1:1       533    30     0,83  2,85                                    7/21     1:1       534    16     0,83  3,21                                    7/13     1:1       535    32     0,84  3,12                                    7/27     1:1       534           0,84  3,22                                    7/49     1:1       533           0,84  3,11                                    7/16     1:1       533    24     0,85  3,05                                     7/101   1:1       534           0,85  2,99                                    7/18     1:1       533    26     0,86  3,04                                    7/19     1:1       533    26     0,88  2,75                                    7/85     1:1       534           0,92  2,49                                    8/30     1:1                     0,73  3,37                                    8/26     1:1       532    31     0,85  3,54                                    8/27     1:1       534    44     0,88  3,13                                    9/30     1:1                     0,75  3,38                                    9/26     1:1       536    34     0,80  3,79                                    9/27     1:1       532    44     0,81  4,16                                    10/24    1:1              34     0,86  3,23                                    11/24    1:1              22     0,82  3,22                                    11/46    1:1              53     0,84  3,20                                    12/28    1:1                     0,79  3,88                                    12/45    1:1                     0,80  3,50                                    50/26    1:1                     0,88  2,48                                    51/26    1:1                     0,90  2,49                                    52/26    1:1                     0,87  2,75                                    53/26    1:1                     0,88  2,83                                    54/26    1:1                     0,87  2,83                                    55/26    1:1                     0,89  2,80                                    56/26    1:1                     0,87  2,69                                    57/26    1:1                     0,87  2,58                                    58/26    1:1                     0,89  2,40                                    59/26    1:1                     0,93  2,26                                    60/26    1:1                     0,93  2,34                                    61/26    1:1                     0,84  2,86                                    62/26    1:1                     0,81  2,81                                    63/26    1:1       541           0,86  2,62                                    68/42    1:1                     0,89  2,64                                    70/42    1:1                     1,06  2,01                                    70/89    1:1                     1,25  1,48                                    72/37    1:1                     0,97  2,11                                    72/94    1:1                     0,97  2,16                                    73/34    1:1                     1,04  1,79                                    75/24    1:1              17     0,90  2,76                                    79/41    1:1                     0,96  2,08                                    79/92    1:1                     1,08  1,67                                    80/76    1:1                     0,82  1,99                                    80/77    1:1                     0,82  2,12                                    80/78    1:1                     0,81  1,82                                    81/76      1:0,6                 0,95  1,32                                    81/77    1:1                     0,86  1,54                                    81/78    1:1                     0,98  1,15                                    82/76    1:1                     0,90  1,82                                    82/77    1:1                     0,90  2,36                                    82/78    1:1                     0,89  1,33                                    83/76    1:1                     0,90  2,20                                    83/77    1:1                     0,89  2,44                                    83/78    1:1                     0,90  2,16                                    84/76    1:1                     0,98  1,57                                    84/77    1:1                     1,04  1,54                                    84/78    1:1                     1,03  1,33                                    86/76    1:1                     0,91  1,45                                    86/77    1:1                     0,88  1,51                                    86/78    1:1                     0,92  1,77                                    87/76    1:1                     0,92  2,14                                    87/77    1:1                     0,97  1,40                                    87/78    1:1                     0,93  1,47                                    102/23   1:1              24     0,92  2,58                                    102/45   1:1                     0,87  2,73                                    103/24   1:1              24     0,84  3,28                                    103/28   1:1              20     0,82  3,44                                    104/40   1:1       558    14     0,96  2,31                                    104/92   1:1       565           1,00  2,05                                    105/23   1:1              25     0,95  2,48                                    106/24   1:1              19     0,82  3,45                                    107/82   1:1       634    16     0,88  2,15                                    107/87   1:1                     1,11  1,29                                    107/95   1:1                     1,11  1,61                                    107/96   1:1                     1,00  1,83                                    107/97   1:1                     1,09  1,67                                    107/98   1:1                     1,04  1,81                                    107/99   1:1                     1,08  1,58                                    107/100  1:1                     1,08  1,77                                    108/82   1:1       621           0,88  2,76                                    108/98   1:1       623           1,00  2,30                                    ______________________________________                                    

The novel dye mixtures have unexpectedly high light fastness values. In some instances, the light fastness of the mixtures is in fact higher than that of the corresponding individual dyes. This is illustrated by way of example below in Table 7.

                  TABLE 7                                                          ______________________________________                                         Dye No.                 LF  h!                                                 ______________________________________                                         3          25           28      22                                             Mixture in weight ratio 1:1                                                                        31                                                         4          25           27      22                                             Mixture in weight ratio 1:1                                                                        48                                                         7          24           11      18                                             Mixture in weight ratio 1:1                                                                        30                                                         ______________________________________                                     

We claim:
 1. Dye mixtures including one or more pyridone dyes of the formula I ##STR178## where R¹ and R² are independently of each other C₁ -C₁₀ -alkyl with or without substitution by C₁ -C₄ -alkoxycarbonyl, C₁ -C₄ -alkoxycarbonyloxy, whose alkyl chain may in each case be interrupted by an oxygen atom in ether function, or phenyl and with or without interruption by from 1 to 4 oxygen atoms in ether function, C₅ -C₇ -cycloalkyl, C₃ -C₄ -alkenyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or or nitro-substituted phenyl, or R¹ and R² are together with the nitrogen atom joining them together a 5- or 6-membered saturated heterocyclic radical with or without further hetero atoms,R³ is C₃ -C₁₀ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl or thienyl, C₅ -C₇ -cycloalkyl, and M is a radical of the formula ##STR179## where X is CH, R⁴ is hydrogen, C₁ -C₆ -alkyl or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, R⁵ is cyano, carbamoyl, mono- or di(C₁ -C₈ -alkyl)carbamoyl, carboxyl, C₁ -C₈ -alkoxycarbonyl or benzimidazolyl, R⁶ is hydrogen, C₁ -C₁₀ -alkyl with or without substitution by phenyl, phenoxy, cyclohexyloxy or pyrazolyl and with or without interruption by from 1 to 4 oxygen atoms in ether function, C₅ -C₇ -cycloalkyl or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, or a radical of the formula NB¹ B² where B¹ and B² are independently of each other hydrogen, C₁ -C₁₀ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, C₁ -C₉ -alkanoyl, C₁ -C₈ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl, pyridylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted benzoyl, pyridylcarbonyl or thienylcarbonyl, and one of the two radicals A and E is nitrogen and the other is a radical of the formula C--R⁷, where R⁷ has the meaning of C₁₋₁₀ -alkyl, with or without phenyl, phenoxy, cyclohexyloxy or pyrazolyl substitution and with or without interruption by from 1 to 4 oxygen atoms in ether function, of C₅ -C₇ -cycloalkyl or of unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl,and one or more azo dyes of the formula II

    D--N=N--K                                                  (II),

where D is a radical of the formula ##STR180## where L¹ is nitro, cyano, C₁ -C₆ -alkanoyl, benzoyl, C₁ -C₈ -alkoxycarbonyl, C₁ -C₈ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl or a radical of the formula --CH═T, where T is hydroxyimino, C₁ -C₄ -alkoxyimino or a radical of an acidic-CH compound H₂ T, L² is hydrogen, C₁ -C₆ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, halogen, hydroxyl, mercapto, unsubstituted or phenyl- or C₁ -C₄ -alkoxy-substituted C₁ -C₆ -alkoxy, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenoxy, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylthio, C₁ -C₈ -alkylsulfonyl or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl, L³ is cyano, C₁ -C₈ -alkoxycarbonyl or nitro, L⁴ is hydrogen, C₁ -C₆ -alkyl, phenyl or tolyl, L⁵ is C₁ -C₆ -alkyl, phenyl or tolyl, L⁶ is hydrogen, cyano, C₁ -C₈ -alkoxycarbonyl, C₁ -C₆ -alkanoyl, thiocyanato, halogen or nitro, L⁷ is nitro, cyano, C₁ -C₆ -alkanoyl, benzoyl, C₁ -C₈ -alkoxycarbonyl, C₁ -C₈ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl or a radical of the formula --CH═T, where T is as defined above, L⁸ is hydrogen, C₁ -C₆ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, cyano, halogen, unsubstituted or phenyl- or C₁ -C₄ -alkoxy-substituted C₁ -C₆ -alkoxy, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylthio, C₁ -C₈ -alkylsulfonyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl or C₁ -C₈ -alkoxycarbonyl, L⁹ is cyano, unsubstituted or phenyl-substituted C₁ -C₆ -alkyl, unsubstituted or phenyl-substituted C₁ -C₈ -alkoxy, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, thienyl, C₁ -C₄ -alkylthienyl, pyridyl or C₁ -C₄ -alkylpyridyl, L¹⁰ is phenyl, tolyl or pyridyl, L¹¹ is trifluoromethyl, nitro, C₁ -C₆ -alkyl, phenyl, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio or C₁ -C₆ -dialkylamino, L¹² is C₁ -C₆ -alkyl, phenyl, unsubstituted or phenyl-substituted C₁ -C₈ -alkylthio, 2-cyanoethylthio or 2-(C₁ -C₆ -alkoxycarbonyl)ethylthio, L¹³ is hydrogen, nitro or halogen, L¹⁴ is hydrogen, cyano, C₁ -C₈ -alkoxycarbonyl, nitro or halogen, L¹⁵, L¹⁶ and L¹⁷ are independently of one another hydrogen, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, halogen, nitro, cyano, unsubstituted or phenoxy-substituted C₁ -C₈ -alkoxycarbonyl, C₁ -C₈ -alkylsulfonyl or unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenylsulfonyl, or L¹⁵ and L¹⁶ are together a radical of the formula CO--NW--CO, where W is C₁ -C₁₀ -alkyl with or without interruption by from 1 to 4 oxygen atoms in ether function and with or without substitution by hydroxyl, L¹⁸ is hydrogen, methyl or chlorine, and L¹⁹ is cyano or C₁ -C₈ -alkoxycarbonyl, and K is a radical of the formula ##STR181## where Y¹ and Y² are independently of each other C₁ -C₁₀ -alkyl with or without substitution by cyano, hydroxyl, halogen, C₁ -C₄ -alkanoyloxy, C₁ -C₄ -alkoxycarbonyl, C₁ -C₄ -alkoxycarbonyloxy, whose alkyl chain may in each case be interrupted by an oxygen atom in ether function, or phenyl and with or without interruption by from 1 to 4 oxygen atoms in ether function, C₅ -C₇ -cycloalkyl, C₃ -C₄ -alkenyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, or Y¹ and Y² are together with the nitrogen atom joining them together a 5- or 6-membered saturated heterocyclic radical with or without further hetero atoms, Y³ is C₃ -C₁₀ -alkyl, C₅ -C₇ -cycloalkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl or thienyl, Y⁴ is hydrogen, C₁ -C₁₀ -alkyl with or without interruption by from 1 to 4 oxygen atoms in ether function, hydroxyl, C₁ -C₆ -alkoxy, C₁ -C₄ -alkylsulfonylamino, mono- or di(C₁ -C₈ -alkyl)aminosulfonylamino or the radical --NHCOY⁸ or --NHCO₂ Y⁸, where Y⁸ is phenyl, benzyl, tolyl or C₁ -C₁₀ -alkyl with or without interruption by from 1 to 4 oxygen atoms in ether function, Y⁵ is hydrogen, C₁ -C₆ -alkyl or C₁ -C₆ -alkoxy, and Y⁶ and Y⁷ are independently of each other hydrogen, C₁ -C₁₀ -alkyl, with or without substitution by cyano, hydroxyl, halogen, C₁ -C₄ -alkanoyloxy, C₁ -C₄ -alkoxycarbonyl, C₁ -C₄ -alkoxycarbonyloxy, whose alkyl chain may in each case be interrupted by an oxygen atom in ether function, or phenyl and with or without interruption by from 1 to 4 oxygen atoms in ether function, C₅ -C₇ -cycloalkyl, C₃ -C₄ -alkenyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, or Y⁶ and Y⁷ are together with the nitrogen atom joining them together a 5- or 6-membered saturated heterocyclic radical with or without further hetero atoms.
 2. Dye mixtures as claimed in claim 1, having a higher light fastness than the individual dyes (I) and (II).
 3. Dye mixtures as claimed in claim 1 wherein R⁴ is methyl.
 4. Dye mixtures as claimed in claim 1 wherein R³ is C₃ -C₁₀ -alkyl, phenyl or thienyl.
 5. Dye mixtures as claimed in claim 1 wherein R⁶ is C₁ -C₈ -alkyl, cyclopentyl, cyclohexyl or unsubstituted or C₁ -C₄ -alkyl- or C₁ -C₄ -alkoxy-substituted phenyl.
 6. Dye mixtures as claimed in claim 1 wherein R⁷ is C₁ -C₈ -alkyl or unsubstituted or C₁ -C₄ -alkyl- or C₁ -C₄ -alkoxy-substituted phenyl.
 7. Dye mixtures as claimed in claim 1 wherein D is the radical of the formula IIIb, IIId, IIIe or IIIq.
 8. Dye mixtures as claimed in claim 1 wherein D is a radical of the formula IIIb, IIId, IIIe or IIIq whereL¹ is nitro, cyano, C₁ -C₄ -alkoxycarbonyl, formyl or a radical of the formula --CH═T, where T is as defined in claim 1, L² is hydrogen, C₁ -C₆ -alkyl or halogen, L³ is cyano, C₁ -C₆ -alkoxycarbonyl or nitro, L⁶ is cyano or nitro, L⁷ is nitro, cyano, formyl, C₁ -C₆ -alkoxycarbonyl or a radical of the formula --CH═T, where T is as defined in claim 1, L⁸ is C₁ -C₆ -alkyl, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl, cyano, halogen or C₁ -C₆ -alkoxycarbonyl, L⁹ is unsubstituted or phenyl-substituted C₁ -C₆ -alkyl, unsubstituted or phenyl-substituted C₁ -C₆ -alkylthio, unsubstituted or C₁ -C₄ -alkyl-, C₁ -C₄ -alkoxy-, halogen- or nitro-substituted phenyl or thienyl, and L¹⁵, L¹⁶ and L¹⁷ are independently of one another hydrogen, C₁ -C₆ -alkyl, C₁ -C₆ -alkoxy, nitro, cyano, unsubstituted or phenoxy-substituted C₁ -C₆ -alkoxycarbonyl, or L¹⁵ and L¹⁶ are together a radical of the formula CO--NW--CO, where W is as defined in claim
 1. 9. Dye mixtures as claimed in claim 1 wherein Y¹, Y², Y⁶ and Y⁷ are independently of one another C₁ C₆ -alkyl with or without substitution by hydroxyl, C₁ -C₄ -alkanoyloxy, C₁ -C₄ -alkoxycarbonyl, C₁ -C₄ -alkoxycarbonyloxy or phenyl and with or without interruption by 1 or 2 oxygen atoms in ether function.
 10. Dye mixtures as claimed in claim 1 wherein Y³ is branched C₃ -C₁₀ -alkyl.
 11. Dye mixtures as claimed in claim 1 wherein Y⁵ is hydrogen, C₁ -C₄ -alkyl, methoxy, ethoxy or C₁ -C₆ -alkanoylamino.
 12. A process for transferring dyes from a transfer to a plastic-coated paper by diffusion or sublimation with the aid of an energy source, which comprises using a transfer on which there is a dye mixture as claimed in claim
 1. 